1. Field of the Invention
The present invention relates to a spindle motor, a disk drive apparatus including the spindle motor, and an electronic device including the spindle motor.
2. Description of the Related Art
A spindle motor for rotating a disk or an impeller is mounted to a hard disk apparatus, an optical disk apparatus, or a fan. The spindle motor includes a stationary portion fixed to a housing of an apparatus and a rotary portion which rotates while supporting a disk or an impeller. The spindle motor generates a torque about a center axis using a magnetic flux generated between the stationary portion and the rotary portion, thereby rotating the rotary portion with respect to the stationary portion.
A conventional spindle motor is disclosed in, e.g., Japanese Patent Application Publication No. 2005-210787 (JP 2005-210787A). The spindle motor of JP 2005-210787A includes a rotating body to which a driving magnet is fixed, a stator disposed in an opposing relationship with the rotating body and provided with coils, a base to which the stator is fixed, an insulation sheet provided in at least a portion between the stator and the base, and a wiring substrate provided in the base at the outside of the motor. Mutually communicating holes are provided in the base, the insulation sheet, and the wiring substrate. End portions of lead wires of the plurality of coils are drawn out to the outside of the motor through the holes.
In this spindle motor, the end portions of the lead wires of the plurality of coils are connected to the wiring substrate by solder at the outside of the motor. As shown in FIG. 5 of JP 2005-210787A, it is necessary to reduce the thickness of the portion of the base where solder is disposed. Particularly, in recent years, a spindle motor is becoming smaller in thickness. Along with the reduction in the thickness of the spindle motor, there is a need to sufficiently secure the rigidity of the base. In order to increase the rigidity of the base, it is desirable to increase the thickness of the base. However, lead wires which constitute the plurality of coils need to be connected to a circuit substrate through the use of solder. In the related art, solder is disposed on a lower surface or an upper surface of a base. In order to limit the height of the solder to fall within the height of the motor, it is required to reduce the thickness of the base. If the thickness of the base is reduced in order to limit the height of the solder to fall within the height of the motor, there is a possibility that the rigidity of the base is impaired. Thus, a demand has existed for the arrangement of solder which secures the desired thickness of the base.